We present the discovery of five millisecond pulsars (MSPs) from the PALFA Galactic plane survey using Arecibo. Four of these
(PSRs J0557+1551, J1850+0244, J1902+0300, and J1943+2210) are binary pulsars whose companions are likely white dwarfs, and
one (PSR J1905+0453) is isolated. Phase-coherent timing solutions, ranging from ~1 to ~3 yr in length, and based on observations
from the Jodrell Bank and Arecibo telescopes, provide precise determinations of spin, orbital, and astrometric parameters.
All five pulsars have large dispersion measures (>100 pc cm-3, within the top 20% of all known Galactic field MSPs) and
are faint (1.4 GHz flux density lesssim0.1 mJy, within the faintest 5% of all known Galactic field MSPs), illustrating PALFA's
ability to find increasingly faint, distant MSPs in the Galactic plane. In particular, PSR J1850+0244 has a dispersion measure
of 540 pc cm-3, the highest of all known MSPs. Such distant, faint MSPs are important input for accurately modeling the total
Galactic MSP population.